Abstract: String-net models allow us to systematically construct and classify 2+1D
topologically ordered states which can have gapped boundaries. We can use a
simple ideal string-net wavefunction, which is described by a set of F-matrices
[or more precisely, a unitary fusion category (UFC)], to study all the
universal properties of such a topological order. In this paper, we describe a
finite computational method -- Q-algebra approach, that allows us to compute
the non-Abelian statistics of the topological excitations [or more precisely,
the unitary modular tensor category (UMTC)], from the string-net wavefunction
(or the UFC). We discuss several examples, including the topological phases
described by twisted gauge theory (i.e., twisted quantum double $D^\alpha(G)$).
Our result can also be viewed from an angle of holographic bulk-boundary
relation. The 1+1D anomalous topological orders, that can appear as edges of
2+1D topological states, are classified by UFCs which describe the fusion of
quasiparticles in 1+1D. The 1+1D anomalous edge topological order uniquely
determines the 2+1D bulk topological order (which are classified by UMTC). Our
method allows us to compute this bulk topological order (i.e., the UMTC) from
the anomalous edge topological order (i.e., the UFC).